Volatile Oil Example- Mentha-Fennel-Coriander-Clove-Cinnamon

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volatile-oils

Volatile Oil Example

Volatile-oils-example

What is volatile oil? What are volatile oil example?

Definition

Volatile oils evaporate on contact to air at room temperature and are the odour producing constituents found in various parts of the plants. The essence or odour of the plant is because of volatile oils so volatile oils are also called as essential oils.

Occurrence

Volatile oils occur widely in nature and are found in plants of about sixty families chief among which are Rutaceae, Umbelliferae, Labiatae, Myrtacease, Pinaceae and Composites Volatile oils are present in whole plant or in specific part of the plant like inflorescence-coriander. Fruits-fennel, leaves-eucalyptus, flowers -lavender, bark-cinnamon, peel-oranges, etc. They are formed in specialized secretory cells such as glandular hairs, modified parenchyma cells, in tubes called vittae or in lysigenous or schizogenous cavities.

Volatile oils are used as flavouring agents or as perfumes in various pharmaceutical Preparations, and some of them are used for their therapeutic action. In plants they mv serve as insect attractants helping in cross-pollination of flowers or in some cases as inert repellents, thus preventing their destruction.

Isolation

Volatile oils are generally obtained from the plant parts containing them by process of distillation. Direct steam distillation along with steam distillation and Water distillation with water are the usual techniques employed. Some volatile oils such as lemon oil are obtained by expression.

Volatile oils, in its fresh state, are colourless liquids. On long preservation they become darker in colour, especially in contact to air and direct sunlight. Volatile oils should be stored in dry place in amber colour container and it should be tightly closed and placed in a cool place. Volatile oils are slightly

Soluble in water but are readily soluble in ether, alcohol and most of the organic Solvents. The purity of volatile oils is checked by determining their densities, refractive Indices optical rotations and boiling points. Volatile oils differ from fixed oils in respects that volatile oils do not leave a permanent grease spot on paper and cannot be saponified by alkalis.

extraction-of-volatile-oils

Chemically volatile oils consist of terpenoidal mixtures of a wide variety of compounds. The basic unit of terpenoids is a five carbon moiety called isoprene (C5H8) unit. These compounds may be hydrocarbons, alcohols, ketones, aldehydes, phenols, ethers, oxides esters, and others.

Hydrocarbon volatile oils contain the compounds called terpenes. These compounds do not contain any functional group and may be branched chained as myrcene or cyclic as limonene. Other hydrocarbons present in oils may be p-cymene, pinene, B-caryophyllene, etc. Turpentine oil is an volatile oil example of hydrocarbon volatile oil drug.

Alcohol volatile oils contain alcoholic compounds which may be acyclic or cyclic in nature. Most common acyclic alcohol found in volatile oils is geranial. Menthol is an important monocyclic alcohol found in peppermint. Other drugs containing alcohol volatile oils are coriander oil, cardamom oil, rose oil, and pine oil.

The aldehydes occurring in volatile oils are Benz aldehyde, cinnam aldehyde, citral, vanillin and anisaldehyde. Important drugs containing aldehyde volatile oils are cinnamon and lemon peel. Ketone volatile oils contain chiefly terpene ketones which menthone, carvone, pulegone or bicyclic such as camphor are the important drugs of this class.

Phenol volatile oils generally have antibacterial, antifungal and antiseptic properties some have slight local anaesthetic and analgesic actions also. Important phenols occurring in volatile oils are eugenol, thymol and carvacrol. Some phenols occur as ethers in volatile oils. Anethole found in fennel and anise is an important volatile oil example. Safrole is Phenolic ether found in sassafras.

Eucalyptus oil is an oxide volatile oil which contains cineole as the chief constituents. It is used a flavouring agent

Ester volatile oils contain esters of wide variety. Terpeneol acetate, geraniol acetate and borneol acetate are of common occurrence, Methyl salicylate is the ester constituent of wintergreen oil. Lavender oil and mustard oil are the other volatile oil example of this group.

What are the uses of volatile oil?

USES:

Volatile oils are used as flavouring, antiseptic agents, carminative, disinfectant, deodorant, antibacterial and antiseptic agents.

MENTHA Family-Synonyms-Biological source-Geographical source-Chemical constituents-Appearance-Uses.

mentha-macroscopic-characteristics

PEPPERMINT OIL

Synonyms

Oleum mentha Piperita, Colpermin, Mentha oil.

Biological Source

The Oil is obtained by steam distillation of the fresh flowering tops of the plants referred to as peppermint Linn belonging to Labiatae . If necessary, it is rectified. Mentha Contain not less than 4.5 per cent and not more than 10 percent w/w of esters calculated as menthol not less than 44 per cent of free alcohols calculated as menthol and not less than 15 per cent and not more than 32 per cent of ketone calculated as menthone.

Geographical Source

Mentha species are cultivated in various parts of the planet . Il grows wild in Europe, while it is cultivated in Japan, England, France, Italy, USA, Bulgaria some other countries. In India, it is cultivated near Jammu and in Tarai region of Uttar Pradesh.

Preparation of Oil

To reduce the bulk, mentha plants are dried to 1/4″ of their weight. It helps in saving the time required for distillation and reduces its cost of production.

Drying directly in sunlight leads to loss of essential oil . Fermentation should not take place during drying of the herb, as it adversely affects the quality and quantity of the oil.

The air-dried material is charged into galvanized iron or mild-steel still. The still designed for this purpose has a false perforated bottom. The steam struggling , generated with the assistance of boiler, is then skilled the drug. It takes about 3 to 4 hours for distillation.

More than 80 per cent of the oil is distilled off during the first half of distillation. Distillation should be completed carefully, as menthol of medicinal and commercial importance comes over within the latter a part of distillation.

The condenser should be made from either aluminium or stainless-steel and will be coiled, so on increase the world of condensation.

The distillate i.e. mentha oil is collected in separating can. Mentha oil is insoluble in water and also lighter than water, which keeps it floating during a separating can. The oil is then decanted and filtered. The average oil content of the herb is found to be 0.5 to 1 per cent (v/w) approximately.

About 100 kg of the oil per hectare of the crop per annum is meant to be satisfactory for commercial purposes.

mentha-macroscopic-characteristics

Description

Colour= white-ish to yellow.
Odour = Characteristic and pleasant.
Taste= bitter followed by cooling sensation,
Solubility= soluble in 70% alcohol, ether and chloroform and insoluble in water.
Table: Description of mentha

Standards

1. It is neutral to litmus paper.

2. Weight per ml is 0.9 to 0.912 grams.

3. Optical rotation = 16° to 30° at 25 C° of temperature.

4. Refractive index is 1.4590 to 1.4650.

Chemical Constituents

Peppermint oil contains chiefly menthol to the extent of 70 per cent in free, as well as, in the form of esters, depending upon variety (like American, Japanese, Indian). American peppermint oil contribute 80 % of menthol and Japanese oil contains 70 – 90 %.

Other important ingredients of the flavour are menthofuran, jasmone, menthone, menthyl isovalerate, menthyl acetate and a number of other other terpene derivatives.

The other terpenes include limonene, isopulegone, cineole, pinene, camphene, etc. Jasmone and esters are liable for pleasant flavour, while menthofuran causes resinification and develops dirty smell.

With the help of steam distillation Mentha oil is obtained from Mentha arvensis, var-piperascens commercially cultivated in U.P, Himachal Pradesh, Punjab, Haryana, Jammu and Kashmir and Central India.

It contains about 80 % of menthol. It is also cultivated in Japan, Brazil and California. The yield of oil is up to 1.2 percent v/w, as compared to 0.8 percent v/w of M. piperita.

Chemical Test

A few drops of peppermint oil are mixed with 5 ml of nitric acid solution (prepared by adding 1 ml of nitric acid to 300 ml of glacial acetic acid dilute liquid procedures blue colour, which on additional heating get blacker and shows copper shades fluorescence after some time it becomes golden yellow.

Uses

Peppermint or Mentha oil is used as carminative, stimulant, and flavouring agents.It has mild antiseptic properties too. It is utilized in toothpaste, tooth powders, shaving creams, and different pharmaceutical dosage forms.

It is also consumed within the preparation of chewing gums, candies, jellies, perfumes and essences. Menthol is manufactured in India by S.H. khelkar and Co, Bhavna Chemicals, Procter and Gamble Ltd, and several others. India produces about 500 tonnes of menthol annually.

Both menthe and menthol have calcium channel blocking activity causing spasmolytic and smooth muscle relaxant effects, and hence useful in irritable bowel syndrome. They show great pharmacokinetic profile when given by enteric coated capsules for release in large intestine.

Muscle relaxant activity is employed to reduce spasm during endoscopy of colon. For this emulsified oil is injected through biopsy channel of the endoscope. Mentha shows digesting property by activating bile flow.

Substitutes and Adulterants: Several species of menthe contain oil. Many times these oils are dementholized and used as adulterants to the drug

Storage

flavorer should be stored in well-filled and air-tight containers shielded from light and in cool place.

Peppermint oil darkens and becomes viscous on storage. If cooled, separation of menthol crystals occurs.

Other species of Mentha such as M. longifolia, M.roundifolia and for flavouring purpose M. spicata (spearmint) produces volatile oils.

CLOVE Family-Synonyms-Biological source-Geographical source-Chemical constituents-Appearance-Uses

clove-macroscopic-characteristics

Synonyms

Caryophyllum, Clove flower, Clove buds.

Biological Source

Clove consists of dried flower buds of Eugenia caryophyllus, Myrtaceae . It should contain not less than 7.0 per cent (w/w) of eugenol calculated on dried basis.

What are fixed and volatile oils?

Geographical Source: it’s indigenous to Amboyna and Molucca islands. Clove is nowadays cultivated chiefly in Pemba, Madagascar, Penang, , Zanzibar, Caribbean islands, India and Sri Lanka.

In India, cloves are grown in Nilgiri, Tenkasihills and in Kanyakumari district of Tamil Nadu state. It is also cultivated in Kottayam and Quilon districts of Kerala,

Macroscopic Characters

Clove Macroscopic Characteristics 
ColourCreme colour to dark brown,
SizeNearly 10 to 17.5 mm length, 4 mm in width, and 2 mm thick.
Odour Less aromatic
Taste bitter and-aromatic along with numbness
ShapeFour layer with four divergents sepals with dome shaped corolla.

The epidermis of the clove is covered with thick cuticle. The epidermis itself consists of straight walled cells and large normocytic stomata.

The oil glands, which are ovoid and schizolysigenous are found in all parts of the drug. Phloem fibres, which are isolated, are occasionally found in the spongy tissue.

Cluster crystals of calcium oxalate and small number of stone cells are found in the drug. Clove does not contain starch.

clove-macroscopic-characteristics

Chemical Constituents

Clove contains about 15 to 20 percent of volatile oil, 10 percent to 13 percent of tannin (gallotannic acid), resin, chromone and eugenin.

The volatile ofl of the drug contains eugenol (about 70 to 90 percent), eugenol acetate, Caryophyllenes and small quantities of esters, ketones and alcohols. Oil of clove is colourless to straw in colour.

It becomes thick and darker in colour on storage, It has specific gravity of 1.038 – 1.06, refractive index is 1.527 to 1.535 and It boils at 250°C,

Chemical Test

If the transverse section of clove is treated with strong needle-shaped crystals of potassium eugenate are observed.

Uses

Clove is employed as a dental analgesic, carminative, stimulant, flavouring agent, an aromatic and antiseptic. It is also used in the preparation of cigarettes. The oil is employed in perfumery and also within the manufacture of vanillin.

Adulterants

1. Mother cloves: dark brown-ripened ovate fruits. They are slightly aromatic and contain starch. They are very poorer in volatile oil content.

2. Blown cloves: it is expanded flowers of the tree. The stamens generally get detached. Blown cloves contain volatile oil which is same in colour to the cloves. The content of volatile oil is less as compared to authentic drug.

3. Clove stalks: clove stalk are used to adulterate the cloves in powdered and are detected by presence of prisms of calcium oxalate. Their ash – value and crude fiber contents are also high.

The authentic cloves should not contain more than 5 percent of stalks to pass the pharmacopoeia limit. Due to similarity in colour, odour and taste, clove stalks are mixed with the cloves. Clove stalks contain only 5 percent of oil.

4. Exhausted cloves: These are the cloves from which oil has been extracted by distillation. Clove became dark in colour when the oil present in it is exhausted. Exhausted cloves float on water.

Storage

Clove and its powder is stored in air-tight bottles and place it in dry and cool places.

CINNAMON Family-Synonyms-Biological source-Geographical source-Chemical constituents-Appearance-Uses

cinnamon-macroscopic-characteristics
fig:Cinnamon

Synonyms

Cinnamon bark; Kalmi-Dalchini, Ceylon cinnamon.

Biological Source

It is dried inner bark of the trees of Cinnamomum zeylanicum Nees, (Syn. Cinnamomum verum J. S. Presl) belonging to family Lauraceae. It should not contain less than 1.0 per cent of volatile oil.

Geographical Source

The evergreen tree of Cinnamon belong to Sri Lanka and Malabar coast of India. It is also found in Jamaica and Brazil. most of the world demands are fulfilled by Sri Lanka and Sri Lanka hence known for true cinnamon.

Macroscopic Characters

Macroscopic Characters of Cinnamon 
ColourOuter- yellowish-brown
Inner-dark yellowish-brown
SizeNearly One mm in length and One cm in diameter.
Thickness-0.5 mm.
Odour Fragrant
Taste Fragrant and sweet followed by warm sensation
ShapeSplintery

The outer surface of the bark is marked by wavy longitudinal striations with small holes of scars left by the branches. The inner surfaces also show the longitudinal striations. Bark is free of cork.

cinnamon-macroscopic-characteristics

Chemical Constituents

Cinnamon bark contains about 0.5 – 1.0 per cent of volatile oil, 1.2 percent of tannins (phlobatannins), mucilage, calcium oxalate, starch and a sweet substance known 3%  mannitol.

The active constituent of the drug is volatile oil. It is slightly yellow (after freshly distilled) in colour andon storage it changes to Red. Bark yields 14 -16 percent of 90.0 percent alcohol soluble extractive.

Cinnamon oil contains 60 – 70% of cinnamaldehyde, 5-10% of eugenol, benzaldehyde, cuminaldehyde.

The other terpenes like phellandrene, pinene, cymene, caryophyllene, etc. Cinnamon oil is yellow to red in colour with specific gravity 1.00 – 1.030, optical rotation 0 to 2 and refractive index 1.562 – 1.582°,

Standards

1. Foreign organic matter <2.0 percent

2. Total ash <6.0 percent

3. Acid insoluble ash <4.0 percent

4. Sulphated ash <6.0 percent

Chemical Test

On addition of a drop of ferric chloride solution to a drop of volatile oil, produces a pale green colour. With ferric chloride, cinnamic aldehyde gives brown colour and eugenol gives blue colour, resulting in the formation of pale green colour. In cassia oil, brown colour is obtained, as it contains only cinnamic aldehyde.

cinnamon-macroscopic-characteristics

Uses

Bark is used as a carminative, stomachic and mild astringent. It is also used as a flavouring agent, stimulant, an aromatic, and antiseptic. Commercially, it is used as a spice and condiment, and also in the preparation of candy, dentrifices and perfumes.

Substitutes and Adulterants

Jungle cinnamon: It is the bark obtained from wild growing trees, which is dark in colour, less aromatic than the cultivated trees, and slightly bitter.

Cinnamon chips: These are pieces of untrimmed bark. They can be distinguished from genuine drug by the presence of abundant cork cells and by poor yield to 90 percent alcohol.

Cultivated Saigon cinnamon: It consists of the bark of the trees of Cinnamomum loureirii (Lauraceae). It is exported from the port of Saigon. It is in China and Japan. The bark is greyish-brown in colour with light patches and sweet taste. Quills are 30 x 4 x 0.7 cm unpeeled and contain 2.5 percent of volatile oil.

Java Cinnamon: It is derived from Cinnamomum burmanii (Lauraceae). Bark is less aromatic, peeled and found in the form of double quills. Histologically, medullary rays contain small tubular crystals of calcium oxalate, not found in C, zeylanicum. It contains about 75 percent of cinnamaldehyde in the oil, it also gives poor yield to 90 percent alcohol as compared to Sri Lanka cinnamon.

Storage: Keep it in well closed containers in cool place, away from light.

FENNEL Family-Synonyms-Biological source-Geographical source-Chemical constituents-Appearance-Uses

Fennel-macroscopic-characteristics

Synonyms

Fennel fruits, Fructus foeniculum.

Biological Source

Fennel consist of dried ripe fruits of the plant known as Foeniculum vulgare Miller, family Umbelliferae, obtained by cultivation. It should contain not less than 0.6 percent of anethole calculated on dried basis.

Geographical Source

It is largely cultivated in Romania, India, France, Russia, Germany, and Japan. In India, it is cultivated in Gujarat, Punjab, Maharashtra, Rajasthan, Uttar Pradesh and West Bengal. Suitable fertilizers are used to prevent weed growth. Ripe fruits are harvested and dried in the sunlight. Fruits are separated by thrashing.

Macroscopic Characters

Macroscopic Characters of Fennel 
ColourGreen-yellowish-brown
Size5 to 10 x 2-4 mm
Odour Strongly aromatic
Taste Sweetly aromatic
ShapeStraight or slightly curved

It is an ortho-spermous fruit. 2 commissural vittae and 4 dorsal vittae are present. The embryo is small implanted in superior end with plentiful oily endosperm. Commissural surfaces of the endosperm are not grooved.

Microscopic Characters

The special features of the histological characters of fennel are the presence of anomyocytic stomata on the epidermis of pericarp and mesocarp containing lignified and reticulate parenchyma.

Parquetry organisation of cells on the internal epidermis of pericarp is another feature of the drug and mutual to all umbelliferous fruits. Vittae, the secretory canals, contain volatile oil and are brown in colour.

Endosperm is prepared up of polyhedral thick-walled cells comprising fixed oil and aleurone grains and tiny design crystals of calcium oxalate. Trichomes and starch grains are absent.

Fennel-macroscopic-characteristics

Chemical Constituents

Fennel consists of 3 to 7 percent of volatile oil, about 20 percent each of proteins and fixed oil.

The chief active constituent of the volatile oil is a ketone, fenchone (about 20 percent) and a phenolic ether anethole (about 50 percent). The other components are limonene, phellandrene methyl chavicol, anisaldehyde, etc.

Fenchone is a colour less bitter liquid with fragrant odour. The anethole is sweet in odour and taste. Oil of fennel is pale yellow liquid with Specific gravity=0.953 to 0.973, refractive index of 1.526 – 1,538 and optical rotation of +/12° to + 24.

Uses

They are used as carminative, fragrant and stimulant. It is also an expectorant. Pharmaceutically, it is used as flavouring agent.

Indian exports of fennel oil during 1995-96 and 96-97 were 17.5 Lakhs and 14.00 lakhs respectively.

Adulterants

Fennel is commonly contaminated with exhausted fennel fruits which can be illustrious by the following tests.

The fruits, from which volatile oil is removed by treating with alcohol, contain less percentage of volatile oil and have a typical odour of fuel oil. Such fruits do not contain fenchone.

If the fruits are empty by the application of steam, they turn dark greenish-brown in colour and contain only traces of volatile oil. They sink in water easily.

Substitutes

Characteristics of Different varieties of fennel fruit used as substitutes

Sr.noVarietySize in mmTasteVolatile oil content
(per cent)
Fenchone
content of volatile
oil (per cent)
1Indian4-7camphoraceous0.7206.70
2Japanese3-4 x 2-3Very sweet2.7010.20
3Saxony10 x 4Aromatic4.7622.00
4Russia or Rumanian4-6 x 1-2camphoraceous4.5018.00
5French Sweet or
Roman
7-8 x 2-3Sweet Aromatic2.1nil

CORIANDER Family-Synonyms-Biological source-Geographical source-Chemical constituents-Appearance-Uses

Fennel-macroscopic-characteristics

Synonym

Coriander fruits

Biological Source

These are fully dried ripe fruit of the plant known as coriandrum sativum linn. (Family-Umbelliferae). The fruit should contain not less than 0.3 % of volatile oil.

Geographical Source

Plant is cultivated throughout European countries, principally in Russia, Hungary and Holland. It is also cultivated Morocco and India. In India, it is widely cultivated in, Andhra Pradesh (Guntur, Anantpur), Maharashtra (Jalgaon and Satara), and West Bengal (Howrah and 24-Paragana districts), Uttar Pradesh Rajasthan and Jammu and Kashmir.

Macroscopic Characters

ColourYellow to brown
OdourAromatic and Spicy
SizeFruits- 2 to 4 mm daimeter
4 to 30 mm length
ShapeSub-globular with ten ridges and eight
Inferior ridges is present. (Cremocarpous fruit)

Main ridges are curvy, while secondary ridges are conventional. It is endospermic fruit. Weight of 100 fennel fruit = 1 gram approximately.

Fennel-macroscopic-characteristics

Microscopic Characters

The epidermis of the pericarp is made up of polygonal tubular cells with stomata. Several epidermal cells contain prisms of calcium oxalate.

Mesocarp consists of inner and outer layer of parenchyma with a layer of sclerenchyma in between them. Inner epidermis of pericarp consists of parquetry cells.

The seed is characteristic to umbelliferous fruits. Starch grains, trichomes and lignified reticulate parenchyma absent. Stable oil globules are present in the endosperm, while volatile oil is present in vittae.

Aleurone grains are existing in polygonal thick walled cellulose parenchyma of endosperm.

Chemical Constituents

Coriander is yields from 0.3 – 1 percent of volatile oil. The fixed oil (13 percent) and proteins (20 percent) are the other contents of the drug.

Volatile oil of the drug contains 90 percent of D-linalool (coriandrol) and coriandryl acetate, and small quantities of L-borneol, geraniol and pinene. Coriander leaves are rich in vitamin A content.

The fruit yields 5 – 7 percent ash. During ordinary storage of crude drug, the volatile oil composition alters considerably.

Coriander oil is pale yellow liquid having specific gravity of 0.863 – 0.875, refractive index 1.462 – 1.472, and optical rotation of + 8° to + 15°.

Uses

The fruits and volatile oil, are used as aromatic, carminative, stimulant and additive agent. Coriander oil is used alongside with purgatives to avoid gripping. It is an element of compound spirit of orange and cascara elixir.

Storage: fruits of coriander are methodically dried and stored in well-closed bottles as they are greatly prone to insects. Substitutes: It is replaced by Bombay coriander fruits, which comprise less volatile oil and are ellipsoidal in shape.

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